Problem: Khan.scratchpad.disable(); William sells magazine subscriptions and earns $$10$ for every new subscriber he signs up. William also earns a $$22$ weekly bonus regardless of how many magazine subscriptions he sells. If William wants to earn at least $$87$ this week, what is the minimum number of subscriptions he needs to sell?
To solve this, let's set up an expression to show how much money William will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since William wants to make at least $$87$ this week, we can turn this into an inequality. Amount earned this week $\geq $87$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $87$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $10 + $22 \geq $87$ $ x \cdot $10 \geq $87 - $22 $ $ x \cdot $10 \geq $65 $ $x \geq \dfrac{65}{10} \approx 6.50$ Since William cannot sell parts of subscriptions, we round $6.50$ up to $7$ William must sell at least 7 subscriptions this week.